It has been found, as a result of a recent congressional committee's investigation, that millions of substandard bolts and nuts have been used in items ranging from military equipment and weapons to the space shuttle and commercial vehicles. The problem has wide-ranging effects which concerns our nation's military as well as our nation's economy. For example, it was found necessary to remove over 1000 M-60 tanks out of the Army's readiness inventory for at least two months to replace defective bolts in the gun mounts. Substandard fasteners were found to have been earmarked for use on both submarines and aircraft catapult systems of the aircraft carriers. The fasteners contained more boron and less carbon than specified in industry standards, making them more likely to break or shear. NASA grounded its fleet of experimental aircraft at one of its facilities pending inspection for substandard fasteners. Widespread counterfeiting and failures of SAE grade 8.0 and other high-strength fasteners have been reported in building and construction sites, coal mines, helicopters, highway bridges and guard rails, nuclear and fossil fuel utilities, grain storage facilities, and commercial trucks and vehicles.
As a result of these fastener failures it became increasingly clear that a need exists for means to permit accurate and timely testing of all sizes of such fasteners to assure that they are safe to use. It is desirable, therefore, to provide a fastener testing apparatus which is versatile enough to test large diameter fasteners, (up to 11/2" diameter, which typically requires a relatively large structure capable of producing large tensile loads) and also to test smaller diameter fasteners, which do not require such large structures and such large tensile loads. It is also desirable that such testing apparatus have the capability of being mobile so as to permit field testing of fastener.
It is an object of the present invention therefore, to provide a testing apparatus for testing various sizes of fasteners under varying tensile loads.
It is another object of the present invention to provide such a testing apparatus which is safe, reliable, compact, versatile and mobile.
It is yet another object of the present invention to provide such a testing apparatus with changeable specimens supporting interfaces which will provide the test apparatus with the versatility which is needed to test fasteners of various sizes.
It is still another object of the present invention to provide such a safe, compact testing apparatus with fast acting actuating means which accomplishes the testing in a rapid and facile manner.